Frost removing composition



Patented Mar. 1, 1949 2,462,970 FROST REMOVING COMPOSITION John B. HoltzclawpRoselle, N. J., assignor, by

mesne assignments, to Standard Oil Development Company, a corporation of Delaware f No Drawing. Application October 28, 1944,. Serial No. 560,905

3 Claims. (01. 106-13) This invention relates to an anti-frost com position, that is, to a composition of matter which prevents frost accumulation on refrigerating equipment from adhering tenaciously to the cooling equipment.

In commercial and household refrigerating equipment, a particular problem is to prevent the building up of too thick a coating of frost. A heavy layer of frost over the refrigerating coils is disadvantageous mainly on account of the reduction of heat transfer from the cooling coils to the surrounding space to be cooled. Usually, in commercial refrigerating plants and household refrigerators, means are provided for defrosting at periodic intervals. In refrigeration plants, considerable time is usually lost in defrosting.

This loss is especially disadvantageous in large scale refrigeration plants. The composition of the present invention is a paste-like material which, when applied to the coils of such refrigeration units, prevents the frost adhering tenaciously to the coils and permits frost formation at any time to be discharged from the coils by simple tapping or such other simple means of dislodging frost from the coils.

The composition of this invention is a highly gelatinous mass capable of cold flow, formed largely from a petroleum oil of non-corrosive characteristics with minor proportions of a water-insoluble soap, a corrosion inhibitor and a freezing point depressant compound. Thus, a typical composition according to the invention is as follows:

' Per cent White mineral oil, vis. 55 Saybolt secs.

at 100 F Oleic acid 8.7 Stearic acid 1.6 Hydrated chemical lime 2.8 Anhydrous calcium chloride, technical 13.0 Sodium nitrite, technical 0.7 Water 0.7

In the above composition, a good grade of substantially odorless white oil is used because of the intended use of the composition in refrigerators containing .edible materials, but for less exacting uses any lubricating oil of suitable viscosity may be used. The oleic acid is present essentially as a reactant with some of the hydrated lime to form a calcium soap. The stearic acid present also reacts with the lime to form a calcium soap by-the amount of which the consistency of the composition as a whole is controlled. The calcium chloride is present largely as a freezing point depressant. While the sodium nitrite and the excess lime present serve as cor rosion inhibitors. The water present in "small amount assists in the compoundingof the composition as a whole and in the'reaction of the various constituents so as to form the desired composition which adheres satisfactorily to the coils and without corrosion.

The amounts in which the mineral oil is present in the composition according to the invention vary from about 60% to. 80%. The waterinsoluble soaps are present in amounts in the final composition ranging in total amounts from about 5% to 12%. The viscid nature of the composition is determined by the presence of an alkaline earth soap usually of st'earic acid, but the alkaline earth derivatives of palmitic, arachidic, myristic, lauric or behenic acids, or mixtures of these compounds, may also be employed in amounts between 1% and 2% by weight of the composition as a whole. The mineral salts present as freezing point depressants are usually calcium chloride but may be magnesium chloride, zinc chloride or other highly water-soluble salt. The polyhydric alcohols, particularly the 1-2 glycols, may also be used as freezing point depressant materials. These freezing point depressant agents may be present in amounts together ranging from about 12% to 18%. Any iron corrosion inhibiting substance together with the lime-and particularly sodium nitrite-is added in small amounts, usually from about 0.5% to 1%. Water in small amounts is also required in the preparation of the composition in order to permit the satisfactory compounding of the various constituents together into a viscid mass capable of cold flow and to permit the freezing point depressant salts to exertthe desired activit in the composition.

In the preparation of the composition according to the invention, illustration will be taken of the specific composition previously given. Thus,

the sodium nitrite and dry calcium chloride are ground together in about 45% of mineral oil, generally using a colloid or ball mill or any such pulverizing equipment to obtain the proper degree of grinding. The oleic and stearic acids arev dissolved with heat in the remainder of the mineral oil. The lime and water are then added to the acid-in-oil solution and the mixture then heated to about 200 F. with good agitation. The mixture thus formed thickens and finally sets to a paste-like mass. After the consistency of the mass has become pasty in character, the suspension of the mineral salts in the mineral oil is added and the mixture thoroughly stirred.

. "Thus, the compositions prepared according to the invention are well adapted for use with all types of refrigeration units. They may be modifled by the use of white mineral oil and relatively odorless grades of fatty acids for use in refrigeration unitsfor lowntemperature storageof. foods.

and in theapreparation'of. ice. As;prepared,-. the? compositions containing the white oils are without odorand have substantially no corrosive veffectsd upon metallic equipment. A single application of the composition to the refrigerationncoilsds :gen.-'

to 18% calcium chloride, 0.5 to 1% sodium nitrite,

- substantially the remainder of said composition erally satisfactory for preventing,thevtenacious.

holding of the frost to the coil'saft'eneasy defrost ing has been effected four or five times; The.sepa,-

ration of the frost from the coils due to the pres-.

"substantialladhesion of frost to refrigerated surfaces-.andlbeing, free of materials which would mice of a thin film of the composition' of 'tlierprese= ent invention normally occurs during the operation of the refrigeration units, if so desireciand.

thus overcomes time losses for periods of defrosting as normally occur withoutuse ,ofthel'compound. V g 7 What is claimed is: 1 1'; A non-corrosive paste-like. composition; of: matter, for preventing thetenacious adhesionof; frost to chilled. surfaces, consisting-essentially of,

. 60 to 8'0 by weight of whitemineral oil,112;to 18 of calciumchloride, substantially theremainder of the. compositionibeing .a,.substantially. Waterinsoluble calcium soap of higher. fatty acids for: imparting a. grease-like consistency toisaid com positionanda small amount, ,not ,morethan 1%, of an. inorganic iron rustinhibitor.

2; A nonr'corrosi-ve paste-like, composition. of". matter for preventingtenacious .adhesion of .frost render foodstuffs inedible on contact therewith.

JOHN B. HOLTZCLAW.

REFERENGES CITED 7 The followingrreferences are of. record in.-the file; of thisspatent-z:

UNITED ST T PATENTS Number Name Date.

345,545- V Smith July ,13, 1886 1,825,151 Keoleian Sept; 29,1931 2,038,724 Eichengrun- ,Apr... 28, 1936 21171 498; Zimmenet a1.. 1"eb.v 23, 1937 2,332,202,- Calkins- ,.0ct. 19, 1943 2333.9,7151- McOmie' J an; 18, 1944. 2,373,727 West-.et al "Apr. 1'7, 1945 GTHER' REFERENCES 'Itechnical Notes .ofsNationalnAdvisoryr Commit tochilled metallic surfaces consisting.essentiallyi tee, on,Aeronautic s; Nov 345, July. l930glpages 1n offiSO. to. by -weight of .white mineraloil,:.,12

and.1'1.. 

